Is leg-length discrepancy after total hip arthroplasty corrected accurately after revision? : functional outcomes and complication rate in 57 patients.

Abstract

Aims: The results of revision surgery to correct leg-length discrepancy (LLD) after total hip arthroplasty (THA) are not clear. Only two previous small series have been published dealing with this issue. The aim of this retrospective study of revision THAs for LLD was to determine the postoperative change in LLD, the functional outcomes, and whether obtaining equal leg lengths influenced function, as well as to report the complication rate and survival.

Methods: This multicentre study included 57 patients: 42 revisions for limb shortening and 15 for limb lengthening. LLD was measured on conventional radiographs. The Oxford Hip Score (OHS) and Forgotten Joint Score (FJS) were collected, along with the number of patients achieving the minimal clinically important difference (MCID) for the OHS.

Results: Revisions were carried out at a mean of 2.8 years after the initial THA. The median LLD decreased significantly from 7.5 mm (IQR 5 to 12) to 1 mm (IQR 0.5 to 2.5) at a mean follow-up of two years (SD 2.4) (p < 0.001). A total of 55 patients (96%) had < 5 mm LLD at follow-up and 12 (21%) had equal leg lengths. The complication rate was 26%. There were 13 mechanical complications (eight periprosthetic femoral fractures, two stem loosenings, two acetabular loosenings and one dislocation), and one periprosthetic infection. Patient satisfaction was high, with a median FJS of 79% (IQR 64 to 98), and 37/48 patients (77%) reached the OHS MCID. Lengthening procedures had significantly worse function postoperatively than shortening procedures (38% vs 91% of patients achieving the OHS MCID (p < 0.001)). Survival was 85% (95% CI 77.9 to 92.5) at two years and 77% (95% CI 66.3 to 87.1) at 4.6 years using re-revision as the endpoint.

Conclusion: When LLD after THA remains symptomatic after conservative management, revision THA should be considered. Revision THA for LLD improved the medium-term functional outcomes with a high patient satisfaction rate, especially for shortening procedures. However, the complication rate, particularly of periprosthetic femoral fracture, was high.